1. Field of the Invention
The present invention relates to a fluorescent material, an organic electroluminescent (referred to as “EL” hereinafter) element and an organic EL display.
2. Description of the Related Art
Since a report on a multilayer element wherein a hole (positive hole) transporting organic thin film and an electron transporting organic thin film are laminated (for example, C. W. Tang and S. A. VanSlyke, Applied Physics Letters, vol. 51, p. 913, 1987), it is expected to apply an organic EL element to a flat panel display as a display element having features such as being self-luminous and high-speed response. Specifically, an organic EL element draws much attention as a large-area light-emitting element that can emit light at a voltage as low as 10 volts or less.
Basically, a multilayer organic EL element is composed of an anode (positive electrode)/a hole transport layer/an organic light-emitting layer/an electron transport layer/a cathode (negative electrode). Regarding the layers, it is also possible to have a structure wherein the hole transport layer or the electron transport layer has also a function of an organic light-emitting layer, just like the 2-layer element disclosed in the above-described C. W. Tang and S. A. VanSlyke.
For an organic EL element to have a high luminous efficiency, it is necessary to have an organic light-emitting layer having a high luminous efficiency. As a structure of an organic light-emitting layer, there have been considered a pigment-doped film wherein a small amount of a pigment molecule having a high fluorescence is doped as a guest in a host material or a main component, as well as a single film composed of a single type of material (for example, C. W. Tang, S. A. VanSlyke, and. C. H. Chen, Journal of Applied Physics, vol. 65, p. 3610, 1989).
Perylene derivatives (for example, Japanese Unexamined Patent Application Publications No. H10-97086, paragraph 0003 and H07-138562, paragraph 0037) and anthanthrene as a blue light-emitting material (for example, Japanese Unexamined Patent Application Publication No. H07-142169, paragraph 0032) are known organic light-emitting layer forming materials.